If possible can any one provide me the link for the material. I have been trying to find the material for a long time now. I can find example for script using these key words ( "-f", "-b" and "-vvv" ), but not able to find the functionality of it.

Google is your friend. Googling sftp z/os returned 116,000 results, the second of which was a link to an IBM page on Ported Tools for OMVS. And clicking on the link on that page takes you to the User's Manual for Ported Tools, where you can find the various options for sftp under z/OS (hint: use the index and find sftp in it).